Method of treating ramie and allied fibers



Patented Feb. 21, 1933 UNITED STATES PATENT GFFICE CHARLES F. KENYON, 0F SHANNOCK, RHODE ISLAND, ASSIGNOR TO ALFRED A. GO- BEILLE, OF SHANNOCK, RHODE ISLAND, PERCY W. NOBLE, J 11., OF RUMFORD, RHODE ISLAND, AND HIMSELF METHOD OF TREATING RAMIE AND ALLIED FIBERS N 0 Drawing.

The present invention relates to the treatment of fibers such as ramie, rhea, China grass and allied fibers, and the purpose of the invention is concerned more particularly With the de-resinatingor de-gumming of such fibers after previous retting or rotting processes have been carried out.

Fibers of this character occur in the form of a fiber bundle within the stalk of the lant, and are first roughly separated from the stalk by de-retting or rotting processes, and thereafter are shipped in de-retted form. Each fiber is surrounded by a sheath or envelope of a normally insoluble resin which must be removed in order to render the fiber susceptible to the usual textile processes of carding, spinning and weaving. This resinous material has a complex chemical form, and may consist of several clifferent types of resin. Various attempts have been made in the past to remove this rela tively insoluble envelope without any considerable degree of success, these attempts normally seeking to attack and dissolve the envelope through the use of a strong alkali or acid. In all cases, however, such prior efforts, if successful in removing the insoluble sheath so completely as to make the fiber practically workable in competition with other textile fibers, have attacked and seriously weakened the cellulose structure of the fiber itself.

I have found that by immersing the deretted fiber with its surrounding insoluble envelope in a hot bath of oil for a definite period of time, I can thereafter completely remove the envelope by treatment with a hot alkaline soap solution capable of emulsifying the oil. Although I am not entirely satisfied as to what action takes place in the carrying out of this process, it is my theory that the initial immersion of the sheathed fibers in the hot oil bath converts the natural resins surrounding the fibers into an emulsifiable resin such as an oleo resin, and that thereafter subjection of the converted resin-coated fibers to a hot soap bath removes the sheath through emulsification. It is a fact that after treatment in the hot oil bath for a definite period of time,

1932. Serial No. 596,149.

the physical character of the resinous sheath is changed through conversion to a hard, inflexible envelope so that the sheathed fibers in this condition have no practical value.

Upon immersion and treatment of this hard, inflexible sheathed fiber in a hot soap solution, the sheath is disintegrated and completely removed from the surrounding fiber without. any weakening or injury to the cellulose content of the fiber itself. In actual practice I have found that immersion of the de-retted fiber in a hot bath of commercial olive oil maintained at a temperature on the order of 250 F. or thereabouts for a period which may average ,10 minutes, is sufficient for my purpose. After completion of this immersion and removal of the excess of oil, I immerse the thus treated fiber bundle in an alkaline soap. solution capable' of forming an emulsion with the oil." The resulting emulsification completely disintegrates theconverted gum resin, and removes it from the fiber. The temperature of the soap solution should be preferably maintained on the order of 212 F.

Although I have not determined with great exactness the limits of temperature at which the process may be effectively carried out, I have found that at temperatures aslow as 160 F disintegration of the resin is incomplete and the results are so'inferior as to make the operation impracticable. On the other hand, the upper limit of temperature should not be so high as to cause carbonization. Temperatures of 250 F for olive oil appear to afford satisfactory results without carbonization, and even somewhat higher temperatures might be satisfactorily employed providing that due care was exercise Although I have found olive oil satisfactory forimy purpose, I believe that certain other oils of vegetable origin may also be satisfactorily used, such as cookingoils in common use, as well as the oils of palm, cocoanut, linseed and various cottonseed base oils. Inasmuch as the fibers after removal of the resin sheath are generally pigmented to some extent, it is desirable, although not necessarily essential, to bleach the resulting de-gummed fiber bundle. I have found that for this purpose immersion of the de-gummed fiber in a 10% solution of sodium hypochloride capable of liberating on the order of 4% chlorine satisfactorily functions as a cold bleach. This cold bleach is followed by a squeeze to mechanically extract, and thereafter the bleaching treatment is neutralizod with a cold sour or acid wash, which in turn is followed by a plain white-wash of cold water, with finish rinsing and drying operations.

The result is a bleached fiber of unusual strength and appearance which may be subjacked to the usual textile operations for incorporation in yarn and cloth.

What is claimed is:- 1.. The method of treating ramie and allied fibers which consists in subjecting the fibers enclosed in the naturally occurring resin sheath in a hot oil bath for a sufiicient period to physically convert the sheath into a hard, inflexible envelope, and thereafter treating the sheathed fibers with a hot soap solution capable of emulsifying the oil for the urpose of disintegrating the resin sheath.

2. The method of treating ramie and alin lied fibers which consists in treating the bath for the purpose of disintegrating the converted resin sheath in the. rm of an emulsion and com letely removing the thus converted sheath rem the interior fibers.

In testimony whereof I have signed my name to this sgecification.

HARLES F. KENYON.

film's sheathed in the naturally occurring resin in a bath of vegetable oil maintained at a temperature exceeding 160 F., and thereafter disintegrating the resin sheath through immersion in a soap solution capable of emulsifying the oil.

3. The method of treating ramie and allied fibers which consists in subjecting the fibers with the naturally occurring resin sheath to treatment with a vegetable oil at. a temperature on the order of 250 F. for

a period suflicient to convert the sheath into a hard, inflexible envelope, and thereafter treating the converted sheath in a hot alkaline soap solution for a period sufiicient to disintegrate the sheath.

4. The method of treating ramie and allied fibers which consists in treating the fibers enclosed in the naturally occurring resin sheath with a hot bath of olive oil,

and thereafter treating the converted hard, inflexible sheath with a hot alkaline soap ible envelope, subsequently treating the converted sheath in a hot soap solution to emnlsify and disintegrate the sheath, and

U5 thereafter bleaching the fibers from which 

